Hyena Friend Preferences
Source: http://www.upenn.edu/pennnews/news/making-friends-friends-benefits-hyenas-penn-biologist-finds
The article highlights a new breakthrough in animal behavioral research conducted by scientists from the University of Pennsylvania, the National Institute for Mathematical and Biological Synthesis, and Michigan State University. The researchers, led by Amiyaal Ilany of the University of Pennsylvania, examined the behavior of hyenas and how they decided which other hyenas to become friends with. They found that hyenas strongly preferred becoming friends with the friends of their friends. The findings showed that Strong Triadic Closure “was the most consistent factor influencing the long-term dynamics of the social structure of spotted hyenas” (Penn News). The hyenas tended to form bonds in groups of three, and were much more likely to form alliances with the friends of their existing friends. Strong Triadic Closure was a bigger determining factor of who the hyenas would be friends than other factors such as “sex and social rank, and environmental effects, such as the amount of rainfall and the abundance of prey” (Penn News).
It is fascinating that animals exhibit similar friend preferences that we do. As the article mentioned, the spotted hyenas demonstrate the property of Strong Triadic Closure, as their strongest bonds are formed through the friends of their existing friends (Penn News). Also, just like humans, the hyenas demonstrated clustering tendencies due to the effectiveness of Strong Triadic Closure, which greatly strengthened their hunting efficiency and safety: “cohesive clusters can facilitate efficient cooperation and hence maximize fitness, and so our study shows that hyenas exploit this advantage” (Penn News). This is similar to early humans, who hunted together in tightly-knit groups to maximize efficiency and safety. Additionally, the spotted hyenas demonstrated the Balance Theorem–they “typically live in large, stable groups known as clans, which can comprise more than 100 individuals. Socially sophisticated animals, these predators can discriminate maternal and paternal kin from unrelated hyenas” (Penn News). This exemplifies the Balance Theorem because all members of each respective group are friendly with each other but all edges between hyena clans are negative. In conclusion, it is interesting how deeply ingrained basic social tendencies such as Strong Triadic Closure and Balance Theorem are in animals, because we typically only associate these properties with humans.